All of the above are antigen presenting cells (APC’s) except –
## **Core Concept**
Antigen-presenting cells (APCs) are crucial components of the immune system. They process and present antigens to T-cells, activating an immune response. Key APCs include dendritic cells, macrophages, and B lymphocytes.
## **Why the Correct Answer is Right**
The correct answer, , is not typically classified as an antigen-presenting cell in the traditional sense like dendritic cells, macrophages, and B cells. While it plays a role in the immune response, its primary function is not antigen presentation.
## **Why Each Wrong Option is Incorrect**
* **Option A:** Dendritic cells are professional antigen-presenting cells known for their potent ability to activate naive T-cells.
* **Option B:** Macrophages are also professional APCs that engulf and digest cellular debris and pathogens, then present antigens to T-cells.
* **Option C:** B cells can act as APCs, especially when they recognize antigens via their surface-bound antibodies.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while multiple cell types can present antigens, professional APCs like dendritic cells, macrophages, and B cells are highly efficient at activating T-cell responses.
## **Correct Answer:** .